Esters are known components for use in fragrance and flavouring applications.
Unsaturated esters have previously been used in diesel fuel applications; in particular, when the unsaturated esters are in the form of, or contained within, fatty acid methyl ester (FAME) compositions.
EP 1731589 A2 discloses palm-based biodiesel formulations with enhanced cold flow properties. Alkyl esters of C6-C18 saturated or unsaturated fatty acids are disclosed as one possible component of the biodiesel.
In U.S. Pat. No. 3,563,715, acrylic acid, methacrylic acid, dimethylacrylic acid, and tert-butyl methacrylate have been shown as some of many monocarboxylic acids and derivatives that increase the octane rating (RON) of leaded hydrocarbon fuels; the effect of those unsaturated components on MON octane rating is not recorded. U.S. Pat. No. 3,563,715 also documents that such ‘lead extenders’ have no effect on octane rating when used in unleaded hydrocarbon fuels.
Ethyl acrylate is also noted, but not demonstrated, as a potential high octane organic compound that could be used alongside organomagnesium compounds in unleaded gasolines in WO 94/04636.
Low carbon number acrylates and methacrylates, for example methyl, ethyl and tert-butyl acrylates and methacrylates, are known to be skin sensitisers, where even a small amount, eg 0.1 wt %, can trigger a problem. Therefore it is undesirable to use such compounds as a component of a gasoline composition.
US 2002/0026744 A1 discloses motor fuel compositions comprising an oxygen-containing component and optionally a hydrocarbon component. The oxygen-containing component disclosed therein comprises a mixture of organic compounds having oxygen-containing functional groups. The oxygen-containing functional groups disclosed therein include alcohols, ethers, aldehydes, ketones, esters, inorganic acid esters, acetals, epoxides and peroxides. The motor fuel compositions of US 2002/0026744 A1 were used as a fuel for various diesel, jet, gas-turbine and turbojet engines.
Esters as a general class of compounds alongside ethers, alcohols, ketones and other oxygenated components, are also proposed as additives for fuels in EP 780460 A1, U.S. Pat. No. 6,156,082, and US 2001/0024966 A1, to improve lubricity or vapour pressure properties. None of those documents however specifically disclose or exemplify the use of low carbon number alkyl alkenoate compounds. EP 780460 A1 is primarily concerned with compatibilisers for Tolad 9103, a mixture of polymerised and non-polymerised fatty acids and heavy aromatic naphtha; U.S. Pat. No. 6,156,082 is concerned with a class of esterified alkenyl succinic acids; and US 2001/0024966 A1 documents the preferred use of C5-C8 alkyl esters of saturated carboxylic acids.
FR 2757539 A1 discloses a fuel and a process for manufacturing a fuel from vegetable matter. The process disclosed involves the production of esters from vegetable matter, and the inclusion of them in a fuel.